We often run into situations in new construction where boxes are, by blueprint, placed directly back to back. Adjoining hotel rooms are often mirror images of each other.
I cannot track down exact requirements or code on placement of boxes directly back-to-back. NEC 300.21 puts horizontal placement of boxes with less than 24" separation on building codes, manufacturers specs, etc.
Every person I've talked to about this has different answers. "Don't do it", "it doesn't matter", "build a sheetrock box or partition around any back to back boxes", "use putty pads", "depends on the boxes" and "whatever the inspector wants" are just a few of them.
As far as I understand, the concerns are: sound transmission and maintaining a wall's fire rating, in that order.
I'm not too concerned about the sound transmission part, but I am concerned about doing my part in keeping a fire rated wall fire rated from ethical, liability, passing inspections, and cost stanpoints, respectively.
Is there any single definitive source of information that covers different box types' (metal, plastic, fiberglass) spacing and firestopping requirements?
I realize I can use adjustable brackets to keep a direct back-from-back situation from occuring, but 24" separation never happens - many places are very picky where they want their devices.
Staggered stud walls make this even trickier, with just 8" between studs and no fire break anywhere along an entire wall (no sealed stud cavities).
Any help or pointers toward the right direction would be greatly appreciated.
ETA: I probably should have posted this in the general category as it's not a cabling issue.
Jack
